Use of the present invention shall be described throughout the specification in relation to golf putters. However, it should be appreciated that the principles of the present invention can be used in relation to attaching other shafts in relation to each other and golf putters is just one preferred embodiment of the present invention.
For example, Canadian Patent Number 2,076,821 relates to an umbrella shaft which uses a spring to position to the shafts relative to each other, so that the shaft can effectively telescope. However, this is not a strong or fixed engagement as this relies on the use of pawls at the end of the spring to hold the shafts. There is no strong frictional engagement.
Golf is a popular recreational game, the object of which is to be able to direct a golf ball into a hole on a green. This is usually done by using a specialised golf club called a putter.
This is usually the trickiest part of the golf game and a common axiom is “drive for show, putt for dough”. This phrase highlights that it is the putting game that determines the success in golf.
Putters come in various forms, commonly called either short, mid (or belly) or long putters. While each of these different types of putters are used differently, a common disadvantage to all is that depending on the height of the golfer, different lengths of putters are required.
There have been many attempts to address this problem and the following patents are representative of these.
Middleton, U.S. Pat. No. 5,733,203, describes a telescoping putter, with 2 shafts, with a “locking screw” to secure the shaft.
Harrison, U.S. Pat. No. 5,649,870, describes a telescopic shaft arrangement where simple friction secures the two telescoping tapered shafts in a semi fixed position.
Mazzocco, U.S. Pat. No. 4,674,747, discloses a golf club having adjustable length shaft retractable between fully extended a collapsed positions. The golf club has plural concentric telescopic interlocking tubular sections which produce a friction lock between the tubular sections in a fully extended positions. There is a club commercially available utilizing this principle (http://www.allinoneglofclub.com).
Sundin, U.S. Pat. No. 5,584,769, describes a shaft which can be constructed of two or more telescopically-adjustable or collapsible members to allow the same to adjust to different lengths for individual golfers. However, Sundin does not specify how the two shafts are to be secured in position.
Lee, U.S. Pat. No. 5,569,096, describes “the shaft inserted into the handle, threadably tightening a locking nut over a flexible ring and a external thread until the flexible ring with squeezed over the shaft prevents the shaft from slipping—thereby effectively locking the shaft in the desired length”.
Napolitano, U.S. Pat. No. 5,282,619, describes a shaft which has a number of telescopic sections where a locking nut and a compression ring permit adjacent sections of the telescopic section to be locked in a fixed position relative to each.
Whilst all the above patented inventions technically allow adjustment, none are both variable in length and in accordance with the Rules of Golf.
The Rules of Golf do not allow readily made adjustment to clubs, and until May 5, 2002 an adjustable length putter has never been determined as legal by the United States Golf Association.
The United States Golf Association is very careful about inadvertent adjustment of golf clubs or putters, and any mechanisms which require either a common tool such as a screwdriver or coin to use, or have no tool.
The current rules as to the limitations of what is and is not allowed as part of an adjustable putter, include the following:                “Appendix II, 1b states that:        Woods and irons must not be designed to be adjustable except for weight. Putters may be designed to be adjustable for weight and some other forms of adjustability are also permitted. All methods of adjustment permitted by the Rules require that:                    i. the adjustment cannot be readily made;            ii. all adjustable parts are firmly fixed and there is no reasonable likelihood of them working loose during a round; and            iii. all configurations of adjustment conform with the Rules.                        The disqualification penalty for purposely changing the playing characteristics of a club during a stipulated round (Rule 4-2a) applies to all clubs including a putter.        
(i) General                In order to preserve the integrity of Rule 4-2 (Playing Characteristics Changed), this rule clearly states that it must not be too easy for a slayer to make adjustments during the course of a stipulated round. This is interpreted to mean that adjustments must require the use of a special tool, such as an Allen key or a Phillips screwdriver. It must not be possible to make the adjustment lust by using the fingers, or something which would normally be kept in a golfer's pocket, such as a coin or a pitch-mark repair tool.        The above restrictions have been included in the Rules in order to encourage the player to make all of the necessary adjustments to his clubs before teeing off, and to protect him from either unwittingly or purposely making adjustments during a round . . . .        Appendix II, 1a states that:        (iii) All parts must be fixed.        This is interpreted to mean that no part of the golf club should be designed to move, nor should it be promoted as doing so. Therefore, if any part of a club were to incorporate moving powder, pellets, liquid, vibrating wires, rollers, tuning forks, or any number of other features which could be considered a “moving part,” it would be in breach of this rule.”        
The inventor of the present invention has attempted to address these issues through his invention as identified in PCT Application No. PCT/NZ02/00123.
This invention is the first invention ever that has been approved by the United States Golf Association for a length adjustable putter.
Problems with previous friction mechanisms include the external bulky nature of the mechanism. This extends out of the shaft and prevents a grip being fitted over the join/mechanism.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.